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Heart Attack

Last updated May 29, 2018

Approved by: Krish Tangella MD, MBA, FCAP

A Heart Attack occurs when the flow of oxygen-rich blood to a section of the heart muscle becomes obstructed. If the flow is not restored quickly enough, then that portion of the heart muscle begins to die.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Acute Coronary Syndrome
  • Cardiac Infarction
  • Coronary Occlusion

What is Heart Attack? (Definition/Background Information)

  • A Heart Attack occurs when the flow of oxygen-rich blood to a section of the heart muscle becomes obstructed. If the flow is not restored quickly enough, then that portion of the heart muscle begins to die.

Who gets Heart Attack? (Age and Sex Distribution)

  • A Heart Attack usually occurs after age 45 years in men and above 55 years in women. However, it can occur in much younger individuals, depending on the risk factors.
  • Also, it has been noted that men are more affected by this condition than women.
  • There are no racial, ethnic, or geographical preferences; all groups are equally affected by this condition.

What are the Risk Factors for Heart Attack? (Predisposing Factors)

The risk factors for a Heart Attack are:

  • Smoking: The longer the smoking history (in pack years), the higher the risk
  • High blood pressure (BP): the longer the duration of high BP and higher the level of BP, greater is the risk
  • High blood cholesterol (total cholesterol), with low HDL cholesterol (good cholesterol), and high LDL cholesterol (bad cholesterol). Decreased levels of good cholesterol implies that there is an increase in the risk of a Heart Attack, equal to the risk of a person, who is a moderate smoker
  • Overweight and obesity; higher the degree, greater the risk
  • An unhealthy diet; which is high in saturated fats and trans fat, cholesterol, and sodium
  • Lack of a regular physical activity (living a sedentary lifestyle)
  • High blood sugar due to diabetes (poorly-controlled diabetes), or due to insulin resistance
  • An advancing age
  • A family history of heart attack, particularly if your father/brother had any heart disease before age 55 years, or if your sister/mother had a Heart Attack before age 65 years
  • Preeclampsia: This condition develops in pregnancy; the key signs being a rise in blood pressure and excess protein in urine. It is linked to an increased risk of serious heart-related medical issues, such as coronary artery disease, Heart Attack, and heart failure
  • After the first incidence of a Heart Attack, chances of a second Heart Attack, is much higher

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Heart Attack? (Etiology)

  • A Heart Attack occurs, if the flow of oxygen-rich blood to a section of the heart muscles suddenly gets blocked
  • A coronary artery disease is the leading cause of a Heart Attack. It is a condition where waxy substances called plaque, build on the inside walls of the coronary arteries. These arteries supply oxygenated blood to the heart. When a plaque ruptures, a blood clot may form at the site of rupture. If this is large enough, it may block the artery completely. If the blockage is not treated soon enough, then a portion of the heart muscles, which are fed by the artery, begin to die. Dead heart tissue is then replaced by scar tissue
  • A less common cause of Heart Attack is termed coronary artery spasm (tightening of the muscle of the artery resulting in blockage). This may occur due to the usage of certain drugs (like cocaine), emotional stress, pain, exposure to extreme cold, or cigarette smoking. A coronary spasm leads to a lack of blood supply to the heart muscles, causing death of the muscles

What are the Signs and Symptoms of Heart Attack?

The signs and symptoms of a Heart Attack are:

  • Sudden, severe, crushing, squeezing chest pain/discomfort
  • Or a change in the pattern of existing chest pain with discomfort

The discomfort is in the center or left side of the chest, and often lasts for more than a few minutes, alternately leaving and returning.

  • A Heart Attack pain can sometimes feel like an indigestion, or a heartburn
  • Discomfort felt in the upper body region;in a single arm (or both arms), the neck, jaw, back, or upper part of the stomach
  • Shortness of breath that may occur before,or with the chest discomfort
  • Sweating, which may be very profuse (breaking out in a cold sweat)
  • Palpitation (feeling that the heart is beating too fast, or irregularly), fainting, cough, anxiety
  • Nausea, lightheadedness, sudden dizziness ; vomiting
  • Sleep problems, fatigue (tiredness, lack of energy)

How is Heart Attack Diagnosed?

A Heart Attack is diagnosed based on the signs and symptoms, medical and family history, and other diagnostic test results. These include:

  • EKG (Electrocardiogram): This test records the electrical activity of the heart. It can show signs of a previous or current Heart Attack
  • Blood tests: Blood tests (such as troponin test, CK-MB test, and serum myoglobin analysis), are used to measure elevated amounts of certain proteins in the bloodstream. During a Heart Attack, when heart muscle cells die, these proteins are released into blood
  • Coronary angiography: This test, often performed during a Heart Attack, uses a dye and special x-rays, to see the insides of the coronary arteries, and detect any blockages
  • Stress test of the heart: Medical studies may be performed to determine blood flow in the coronary arteries of the heart. This assessment of blood flow can either be performed using a treadmill exercise test, or using a pharmacologic stress test of the heart
  • In a treadmill exercise test, an individual is made to walk or run on a treadmill. Slowly the intensity of the exercise is increased. During this test, the heart is monitored, looking for any abnormal function on an EKG. Once an abnormality is observed on the EKG, the treadmill stress test is stopped, by the physician. Lower the exercise tolerance usually indicates a more severe coronary artery disease
  • A pharmacologic stress test is performed on an individual, who cannot be tested on a treadmill exercise test. In this test, a drug that increases the heart rate is administered. This drug increases the heart rate, stimulating it like one would see during an exercise. Abnormalities observed in the EKG, indicate the presence of a coronary artery disease

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Heart Attack?

The possible complications that arise from a Heart Attack include:

  • Heart failure, both acute and chronic
  • Aneurysm or rupture of the myocardium, due to tissue damage
  • Mitral valve regurgitation caused by a rupture of the papillary muscles, which is attached to the mitral valve
  • Arrhythmias (irregular heart rhythm), due to atrial/ventricular fibrillation, ventricular tachycardia
  • Long-term complications, like atrial fibrillation, heart failure, and increased risk of Myocardial Infarction (Heart Attack)

How is Heart Attack Treated?

A Heart Attack is a medical emergency. Call  911 or your local medical emergency number for healthcare in your area. A variety of medications may be given right away to improve circulation of the coronary arteries, supplying blood to the heart. These include:

  • Sublingual (below-the-tongue) nitroglycerine medication
  • Oral aspirin
  • Betablockers
  • Ace inhibitors
  • Anticoagulants or blood thinners
  • Antiplatelet drugs

Other measures include:

  • Percutaneous coronary intervention (PCI), to place stent at the site of artery blockage
  • Fibrinolysis (mechanism to prevent clot formation) with clot-busting medications, is recommended in those with one type of Heart Attack, called STEMI (ST-Elevation Myocardial Infarction). ST indicates the ‘S’ and ‘T’ wave present on an EKG, as part of the PQRST electrical wave complex, which occurs during the single beat of the heart
  • Oxygen therapy, using higher concentration levels of oxygen
  • Surgery (such as coronary artery  bypass grafting) may also be used to treat a Heart Attack. Here, a healthy artery or vein is connected/grafted to the blocked coronary artery

How can Heart Attack be Prevented?

Heart Attacks may be prevented by:

  • Heart healthy lifestyle: This includes having a healthy diet mostly consisting of whole grains, fruits and vegetables, with poultry, fish, lean meats, milk items (milk and milk products should be low-fat or fat-free)
  • If overweight or obese, then physical activity and diet may be employed to maintain a reasonable weight loss plan. Being physically active can improve fitness and health
  • Cessation of smoking
  • Paying attention to and keeping in control,other medical issues like diabetes, high blood pressure, high blood cholesterol

What is the Prognosis of Heart Attack? (Outcomes/Resolutions)

  • The prognosis of a Heart Attack varies greatly. It depends on the individual’s health, the extent of the heart damage, and promptness with which medical treatment is given
  • If heart damage is extensive, then complications like heart failure, arrhythmias, may occur. These could be life-threatening. Moreover, after a first attack, the chance of a second Heart Attack is much higher
  • Prompt medical therapy in a mild Heart Attack, can result in an excellent prognosis. On the other hand, a delayed medical attention, for an individual with severe heart disease, may result in poor prognostic outcomes
  • Currently, excellent treatment measures are available for Heart Attacks, such that they can save lives, and avoid long-term complications/disabilities

Additional and Relevant Useful Information for Heart Attack:

  • Heart Attacks, along with strokes (collectively referred to as cardiovascular diseases), are leading killers of both men and women around the world
  • Cardiac rehabilitation is a medically supervised program to help improve the health and well-being of individuals with heart-related medical issues, and also reduce future risk of a heart condition

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Oct. 2, 2013
Last updated: May 29, 2018